A new method for the analysis of Pt(II) in urine has been developed which utilizes high pressure liquid chromatography. Application of this method to patients on Pt (NH3)2Cl2 chemotherapy indicates that platinum is excreted in a first-order manner for the first 3-4 hours, when an abrupt change in slope occurs with the onset of a low-level, nearly constant rate of excretion. Initial excretion rates will be correlated with clinical platinum toxicity. The coordination chemistry of Pt(II) is being studied in order to learn more about possible mechanisms for nephrotoxicity. Compounds with the potential for blocking platinum nephrotoxicity based on a chemical rationale are currently under study in animal model systems.